Computing-machine.



G. WALKER.

COMPUTING MACHINE.

APYLIGATION FILED JULY 25, 1912.

Patented June 2, 1914 2 SHEETS-SHEET l- G. WALKER.

COMPUTING MACHINE.

APPLIGATION FILED JULY 25, 1912.

1,098,856, Patented June 2,1914.

2 SHBETS-SHEET 2.

\X/ITIJEESEE:

UNITED STATES PrglENT OFFICE.

GEORGE WALKER, OF NEWTON CENTER, MASSACHUSETTS.

COMPUTING-MACHINE.

Application filed July 25,

To all whom it may concern Be it known that I, Gnome WALKER, a citizen of the United States, and resident of Newton Center, in the county of Middlesex and State of Massachusetts, have invented new and useful Improvements in Computing-Machines, of which the following is a specification.

This invention relates to a computing machine, and particularly to a machine for adding and subtracting.

The invention consists principally in novel and improved tripping or carrying mechanism of simplified and improved construction and operation; in means whereby the machine may be automatically placed in condition for either adding or subtracting the amounts represented by the keys dcpressed, by merely shifting a single hand lever; in mechanism for automatically throwing the type wheels into the proper position for printing the sum, Whenever the sum key is depressed, regardless of whether said hand lever stands in adding position or in subtracting position; and in adapting said tripping or carrying mechanism to computation according to non-decimal systems as well as to decimal systems. In my present device the tripping or carrying is in no way dependent upon the action of springs but is performed positively and directly by the power which operates the machine in response to the key action. My improved carrying mechanism also includes a block or stop which automatically limits the movement of the tripping parts, thus positively arresting the movement of the wheels actuated thereby at the proper predetermined point. \Vheu said hand lever which determines whether the machine will add or subtract, is thrown to adding position, the deression of the keys without further attention on the part of the operator willautomati- (ally add and print the amounts represented by the keys depressed, and when said hand lever is thrown to subtracting position, the depression of the keys without further attention on the part of the operator will automatically subtract and print the amounts represented by' the keys depressed.

Other features will hereinafter be mentioned and particularly'pointed out in the claims.

For the purpose of illustration, I will describe the present invention as applied to the computing machine shown in Letters Specification of Letters Patent.

Patented June 2, 1914. 1912. Serial No. 711,504.

Patent of the United States No. 996,173, granted to me June 27, 1911, but it will be understood that the invention is not limited to that particular machine but is of general application.

In the accompanying drawings which illustrate certain embodiments of the invention, and show only such parts of the computing machine of my said former patent as are essential to a clear understanding of the invention,Figure 1' is a side view of my improved carrying mechanism, and the devices for adding and subtracting, for operating according to the decimal system, applied to the gear wheels Which operate the type wheels or number wheels of the machine, the parts being shown in subtracting position; Figs. 2 and 3 are fragmentary side views showing the changes necessary to adapt the device to computations according to a non-decimal system,the English money system being used as an example; Fig. 1 is a detail view of a art of the carrying mechanism hereina er described; Fig. 5 is a fragmentary view showing the position of certain of the parts of Fig. 1 when shifted to adding position; and Figs. 6 and 7 are detail views showing the mechanism for shifting the parts from adding to subtracting positions or vice versa.

Referring to the drawings, 1, 1, etc, represent the main gear wheels or number wheel gears of the machine, journaled on shaft 4, and meshing with gear wheels 2, 2, etc, which respectively carry the numberwheels or type wheels 3, 3", 3", etc, journaled on shaft 5. Said gear wheelsand number-wheels may be constructed and arranged as'shown in my said former patent. Instead of the tripping or carrying mechanism therein shown, my improved tripping or carrying mechanism, as herein exemplified, comprises the following parts: a stud 733 (Fig. 6) projects from the inside of one of the side frames of the machine, through a hole in the rocking piece 7 32, which swings on stud 733. Another stud 739 also projects from the inside of said side frame through a hole in the rocking piece 738, which swings on stud 739. Parts 732 and 738 are connected by rod 737. Stud 73s projects from the inside of said side frame into the path of swinging piece 732 acting as a stop to limit the movement of part 732. A spring 735, connecting the end of swinging piece 732 and a pin 73? projecting from the inside of said frame, tends to urge the nose 732 of piece 732 toward stud 734. The lower end of swinging piece 738 is connected by rod 740 with arm 741, which is solidly fastened to shaft 742, extending between side frames of the machine with its ends turning therein. Duplicates of the foregoing parts are mounted just inside the opposite side frame of the machine and are shown in Fig. 7, 732 and 738 representing swinging pieces like parts 732 and 738; nos e,'732 corresponding to 732; studs 733, 739 and 734' corresponding to studs 733, 739 and 734; connecting rod 737 corresponding to rod 737; and spring 735 and in 736 corresponding to spring and pin 3,5 and 736. The correspondingpartsat the two sides of the machine are arranged directly opposite one another. Rod 740 correspondlng to rod 740, connects the lower end of piece-738 with arm .74l wh i ch is fast on shaft 742.

Manually operated means for actuating pieces 734 and 734,-and 738 and. 738, are provided, consistingof a hand, lever or ship .p er 76( which turns on shaft 74 and engages pin 762 on M 1 7 6l.solidly fastened to shaft 742 close to lever 760. The lever 760 projects through a slot d inthe cover or top frame. I) vof .the machine andis made with sufii cient lateral resi iency to spring into and engage notches or shoulders provided in the sides of said slot in a manner well understood for holdingsai'd lever 760 at the extremes ofits forward and backward throw. In the position shown in Fig. 7, the 'lever ,760 is thrown forward, in. thedirection of the arrow to the limit of its movement in that direction;v ,Snch; forward movementof lever 760 swingsv arm 761 by pin 762 in the same direction, thereby rotating shaft 742 and swinging the rocking parts 732 and 732., and 738 and 738 in a clockwise direction, asviewed in the drawings. When the lever 760 swings back in the opposite direction from the arrow, spring 735 and 735 will swing said rocking pieces in a counterclockwise direction, the pin 762 following the side of lever 760, against which it is pressed by the action of said springs.

Extending between rocking pieces 738 and 738'. are shafts 5 and v725;'and extending be tween rocking pieces 732 and 7 32- are shafts 728 .and 731. The series'of gear wheels 2, 2', etc., carrying type wheels-3, 3', etc., are assembled on shaft 5. A set of intermediate gear wheels 724, 724, etc., one meshing with each of said gear wheels 2, 2', etc., are as sembled on shaft 725. Said two sets of ear wheels are adapted to engage the num erwheel gears, 1 1, etc., one set at a time, so that when rocking pieces 738 and 738 are swung to v their extreme position in a counter-clockwise direction the gear wheels 2, 2 etc., will directly engage the number- .in'Fig. 5)..

said intermediate gears 724, 724', etc., standing clear of the number-wheel gears; and when said rocking pieces are swung to their opposite extreme position, in a clockwise direction, said gear wheels 2, 2', etc., will be in train with said nun1ber-wheel gears 1, 1', etc., through said intermediate gears 724, 724", etc., (as shown in Fig. 1), thus reversing the direction of rotation of the type wheels 3, 3, etc., assuming the rotation of the number-wheel gears 1, 1, etc., to be always in the same direction. Assembled on shaft 728 is a set of gear wheels 726, 726', etc., one for each of said number-wheel gears 1, 1, etc., except the last in the series progressing from the unit column upward to the columns of higher order. On shaft 731 is assembled a set of gear wheels 729, 729', etc., meshing with gear wheels 726, 726*, etc., there being one such gear wheel of the 729 set for each gear wheel of the 726 set. .These two sets of gear wheels, which may be termed the carrying or tripping gears, are adapted to engage the main gears 1, 1, etc., one set at a time, the gear wheels ofthe 726 set being in mesh with said number-wheel gears when the rocking parts 732 and 732 are swung in acounter-clockwise direction,

meshv with the number-wheel gearsw ien said rocking parts are swung in a clockwise direction,

The gear wheels of the several sets 2,v 724,

726 and 7 29 are all, alike. Each gear wheel.

726,,carriesfastened to its side a tooth or projection 727 (best shown in Fig. 1)., and each "gear: wheel 729 carries fastened to its side a tooth or projection 730 (bestv shown tween'the side frames of the machine, at

either side. of said carrying gears. Arm 749 :swings on shaft 750, arm 752 swings on shaft 751, and an oscillating bar 748 is hung on the lower ends of arms 749 and 752, to swing between main gear wheel 1 and the adjacent main gear wheel 1'. Bar 748 is in the same vertical plane with teeth 727 and 730. On the .end of bar 748 is hung a double ended pawl 747, which is in the same plane with and operates gear wheel 1. There is-a bar 748 and pawl 747 cooperating with each set of carrying gears 726, 729.

A set of springs 744 hung on rod 745, which is supported between the side frames of the machine, with one end engaging rod 743, also supported between said side frames, and the other end engaging pawls 747, tends to press the upper ends of pawls 7 47 against the teeth of the number-wheel'gears 1, 1, etc., and at the same time to throw the bars 748 toward the right into the position shown in the drawings, with their ends resting against rod 746, which extends between the side frames of the machine'and acts as a stop for bars 748.

Shafts 750 and 751 extend be- Each gear wheel lock 18 (of which there is one for each number-wheel gear 1, 1, etc., as described in my said former patent) is provided with a finger 18 projecting upwark back of and in engagement with the end of arm 752. Each bar 748 has two upwardly projecting teeth 748 and 748 (best shown in Fig. 4). Tooth 727 of gear wheel 726 operates against tooth 748", and tooth 7 30 of gear wheel 729 operates against tooth 748 Standard 759 (Fig. 7) mounted solidly on the base of the machine frame, carries stud 758 on which is pivoted bell crank lever 7 56. A pin 757 projects from the lower arm of bell crank 756 under rod 167. The upper arm of bell crank 756 is connected by rod 755 with arm 754, which is fastened solidly on shaft 742 over bell crank 756.

As described in my said former patent, the type wheels carry on their peripheries, a series of types or numerals from 0 to 9 inclusive arranged counter-clockwise and when in normal position before the 1nachine has been operated the 0 type will be in position A, (Fig. 1).

Adding-When the machine is to be operated for adding, lever 760 (Fig. 7) is thrown to the left as viewed in the drawings swinging gear wheels 726 and 2 into mesh with the number-wheel gears 1, as shown in Fig. 5. The type wheels or number wheels 3 will then be actuated directly from said number-wheel gears, as in my said former patent, and when number-wheel gear 1 is rotated counter-clockwise, by the depression of a key, as explained in my said former patent, the amount represented by the key will be added on said type wheel. At the same time gear wheel 726 will be turned by number-wheel gear 1, the same number of teeth as gear wheel 2. When nine has been added on type wheel 3, the tooth 727 will have been turned to the point where it will rest against the face of tooth 748" of bar 748. If new a key of the same column'is depressed, carrying type wheel 3 to O or beyond, the tooth 727 will swing bar 748 endwise toward the left, thereby causing pawl 747 to turn the next gear wheel 1 of higher order, one tooth, and adding one on the type wheel of the next higher column. At the end of the key stroke, bar 748 will fly back into normal position against step 746, under the influence of spring 744. It will be noticed that there is a slight space between the end of pawl 747 and the tooth of gear wheel 1 against which it is to operate, thus affording a little lost motion after the bar 748 starts to swing to the left. lVhile pawl 747 is traveling this space, arm 752 acts on the finger 18 of lock 18, lifting said lock out of the gear wheel in time to allow the gear wheel to be rotated when pawl 747 reaches the tooth of said gear wheel. At the end of the movement of pawl 747 the right hand or lower end of said pawl swings int engagement with the teeth of gear wheel 1 and acts as a block or stop to prevent said gear wheel 1 from being rotated more than the distance of one tooth during said tripping or carrying operation.

Subtracting.-1n order to place the ma.- chine in condition for subtracting instead of adding, all that need be done by the operator is to throw hand lever 760 in the direction of the arrow to the position shown in Fig. 7. The parts will then be in the positions shown in Figs. 1, 6 and 7, with gear wheels 724 anad 729 in mesh with gear wheel 1, and gear wheels 2 and 726 out of mesh with gear wheel 1. If new a key is depressed, gear wheel 1, still rotating counterclockwise as described in my said former patent, will act through intermediate gear 724 to turn type wheel 3 counter-clockwise, that is, in a direction opposite to that taken when the machine is adding, and instead of turning the types forward from 0 toward 9 will turn them backward from 9 toward 0, thus subtracting on the type wheel the amount represented by the key being operated. In substracting, as will be understood, the carrying of the gear wheel and type wheel of higher order from a wheel of lower order, must take place as the latter is passing from 0 to 9 instead of from 9 to O as in adding.

The carrying for subtraction is accomplished by the tooth 748 the tooth 730 and gear wheel 729. It will be observed that when the type wheel 3 stands with O in printing position A, tooth 730 on gear wheel 729 is in position against tooth 74S of bar 748. 'If gear wheel 1 is again rotated a distance, for example of one tooth, bar 748 will be swung by tooth 730, and pawl 747 will turn the next gear wheel 1, a distance of one tooth, thereby subtracting one on type wheel of the next higher order. Thus the carrying tooth 730 for subtracting is adjusted to carry the gear wheel of higher order when its own type wheel is passing from 0 to 9, while the carrying tooth 727 for adding is adjusted to carry the gear wheel of higher order when its own type wheel is passing from 9 to 0 It will be observed that when either gear wheel 726 or 729 is in mesh with gear wheel 1, it rotates in a clockwise direction and the tripping tooth 727 or 730 as the case may be, travels toward the teeth of bar 748, but when either gear wheel 726 or 729 is out of mesh with gear wheel 1, it rotates counterclockwise and the carrying tooth 727 or 730, as the case may be, recedes from the point where the carrying is effected. Thus the carrying teeth are automatically maintained in position to trip or carry at the proper point whenever either set of carrying wheels,

ward. The top frame or cover D may be marked frk dd and Subtract, if desired, opposite the two positions of lever 760, to ndicate the direction in which the lever 760 1s 1to be thrown to accomplish the desired resu t.

Ina machine thus constructed for adding and subtracting, it will be seen by reference to the parts shown in Fig. 1, and by reference to my said former Patent No. 996,173 showing the relation between the type wheels and the printing hammers and paper cz'irryirfg devices, that in order to bring the type wheels 3 into proper position to print the sum, that is, in'pos'ition nearest the hammers and in alinement therewith, the type wj h'eels shouldbe thrown away from gear wheels 1 to subtracting position (as in Fig. 1 wheney'er the sum is to be printed. Of course if the machine is already in subtractin'g position when. the result, is printed, no

change of positionis necessary; but if the machine is at tlie'tiine being used for adding, it is neoess'arythat the type wheels shifted to racting position. This is acco p'lish'ed automatically whenever the sum key f for operating the hammersin unison print the sumis depressed, by the following 'inechani's in: described in my said former. whenever the sum l'teyf is depressed, the 'rod or link 167 for .l actuatingthe hammers, moves in the direction ofth'earrow in Fig. 7. VAs suniing now that the lever 7G0 i's'thrown to adding positio'tn, that is, toward the left, and that the tripping 'gearsaiid type wheelsare onscquently in the position shown n Fig. o, arm 761 will be thrown to the left under the influ'ence'of springs and 735' with pin 762 'ie stingagainst lever 760, and bell crank m6 Wlll be swung in the same direction throwing pin 757 toward the projection 167" on'rod 167 (Fig.7), If the sum key is depressed with the parts in this position, the projection 167: will engage pin and swing bell crank '75\'3 so as to carry all the parts excepting lerer 760 into the positions .showniii Figs 1, (3 and 7, thus bringing the type wheels 3 into proper position for printing the sum. Vhen the sum key is released, permittingfrod 167 to return to its initial position, the other parts will automatically return to the addin position underthe influence of springs 735 and 735, so

that the adding process may be continued exactly where it left oil", without requiring any preliminary adpistment or manipulation by the operator. If the result is to be printed with the lever 7G0 already in subtracting position, as shown in Fig. '7, the movement of rod 167 in response to the depression of the sum key will not actuate bell crank 756, but merely move projection 167 idly up to pin 757. Therefore, rod 167 will merely actuate the hammers as described in my former patent without affecting the mechanism which controls the adding and subtracting position of the other parts. Another reason exists for always having the number wheels brought to the same position when the sum is, printed, in addition to the necessity of bringing them close to the hammers, namely: the alineinent lock, consisting of bar 700 onsarms 7'00 and 700", for engaging notches in the number wheels to insure their true alinement. This alinenient lock is actuated by rod 702, spring 701 and arm 703 fast on rock shaft 105. these parts constitute the subject of another application to be filed simultaneously herewith, they nced not be more fully described herein. Thus the machine may be thrown into adding or subtracting positionas desired, by merely shifting lever 760, and yet whenever the sum key is depressed, which actuates rod 167, the type wheels willhbe automatically thrown to the proper position for printing the sum (if they are 'not already in that position) and will be automatically restored again to their initial position. a .1 s

Non-decimal system. The machine thus far described, as exemplified particularly in Figs. 1 and 5, is a machine for computing by the decimalsystem. The invention, however, is equally well adapted for co nputation by any non-decimal system, and for the purpose of illustration I will. describe the modifications necessary to adapt the invention to compute according to the English money system of pounds, shillings and pence.

Fig. 2 illustrates the mechanism for adding and subtracting in they pence column. The keyboard .and other parts of the machine not directly connected with the present invention, may he as shown in that part of my said fOllllUl patent describing the English money machine. Gear wheels 2", 724*, 726 and 729 '(Figs..2 and 3) correspondiug to the similar parts in other figures, have twelve teeth each, instead of ten,

and type wheel 3 also has twelve numerals,

from O l to 11 inclusive. The tripping teeth are adjusted to operate the units column of the shillings wheels, when the pence type wheel 3". passes from l1 to 0 for adding, and from O to 11 for sub tracting. In other respects the construction and operation of the parts is the same asin the decin'ial system mechanism already; described. Fig. 3 shows the corresponding parts in the tens column of the shillings wheels. There being twenty shillings in a pound, there are two shillings wheels and two shillings columns, the units shillings wheel being numbered from 0 to 9 as in the regular decimal system, and the tens shillings wheel 3 being provided alternately with the numeral 1 and blank spaces as shown in Fig. 52 of my said former Patent 996.173. Gear wheel 726 carries on its side five tripping teeth 727 and gear wheel 729 also carries on its side five tripping teeth 730. It will be understood that at the side of the shillings columns are the pounds columns which are constructed and operated according to the regular decimal system already described. Whenever gear wheel 1 (Fig. is moved a distance of two teeth (the carrying teeth of gear wheels 726 and 729 being spaced apart the distance of two gear teeth) the unit wheel of the pounds column will be rotated one tooth or one space for the addition or subtraction of one in that column, so that whenever the combined shillings type wheels pass from 19 to O for adding, or from O to 19 for subtracting, the units pounds colnmn is rotated either forward or backward one step, thereby either adding or subtracting one in that column. In other respects the operation of the device is the same as already described.

Should it be desired to use my new form of tripping or carrying -mechanism in an adding machine which is not also a sub tracting machine, gear-wheels 726 may be mounted on a fixed shaft instead of an oscillating or movingshaft, that is, shaft 728 may be fixed in the side frames of the machine so that gears 726' are permanently in mesh with number wheel gears 1, in the position shown in Fig. 5. Gear wheels 729, having no otlice to perform in the adding operation, may be dispensed with. Intermediate gear wheels 724 may also be dispensed with, and the gears 2 of number wheels 3 will be permanently in mesh with gear wheels 1, as shown in my said former patent. Also the hand lever 760 and the parts operated thereby will be omitted since the tripping gear wheels and the number wheels are not to be rocked but are permanently in adding position. The tripping or carrying will then be performed through the carrying gea rs 726 and bars 748, as already described.

In a tripping or carrying mechanism constructed as herein described, either for adding and subtracting, or for adding'alone, the pawl 747 will not interfere with thefree and independent rotation of gear wheel 1, which the pawl operates in carrying, so that said gear wheel 1' may be operated directly from the keys of the machine; nor will the rotation of gear wheel 1' affect gear wheel 1 since the pawl will drag idly over the teeth of gear wheel 1 when the latter is rotated from the keys.

Inasmuch as multiplication is a. species of addition and division is a species of subtraction, it will be understood that the mechanisms herein described are applicable also for multiplying and dividing machines.

When the above described carrying mechanism is used instead of that shown in my said former Patent No. 996,173, which contains a cam wheel (see cam wheel 1 11, Fig. 54 of my said patent), I provide pins or studs 753 for actuating lever 180, which controls the hammer blocking devices (not shown). The action of said studs in place of the cam teeth will be obvious by reference to my said patent, and as the hammer blocking mechanism forms no part of the present invention it need not here be more explicity described.

I claim:

1. In combination with the number-wheel gears of a computing machine having locks normally holding said gears against rotation, a carrying device comprising a tripping gear in mesh with one of said number wheel gears, and mechanism actuated by said carrying gear adapted to carry a number-wheel gear of different order and to unlock the lock engaging such number-wheel gear during said carrying operation.

2. In combination with the number-wheel gears of a computing machine, a carrying device comprising a tripping gear in mesh with one of said number-wheel gears, mechanism between said carrying gear and a number-wheel gear of, different order adapted to carry the latter, said mechanism also adapted to permit the independent rotation of the number-wheel gear carried thereby, a movable stop adapted to arrest the numberwheel gear being carried at the end of its predetermined carrying movement, and locks normally holding said number-wheel gears against rotation, said tripping mechanism also adapted automatically to unlock the lock engaging the number-wheel gear being carried during its carrying movement.

3. In combination with the number-wheel gears of a computing machine, a carrying device comprising a carrying gear in mesh with one of said number-wheel gears, and

mechanism between said carrying gear and said carrying mechanism to its initial position at the end of each carrying operation.

4. In combination with the number-wheel gears of a computing machine having locks vr g gear t normally holding said gears against rotation, a carrying device comprising a carryin'g' gear in mesh with one of said numberwheel gears, an oscillating bar at the side of each number-wheel gear, a projection 0n said carrying gear to actuate said oscillating bar, a pawl actuated by said oscillating bar adapted to carry a number-wheel gear of different order, and conneetion between said barand the lock of the gear being carried to unlock said lock during the Carrying operan.

In combination with the number-wheel gears ota computing machine, a carrying device comprising a tripping gear in mesh with one of said number-wheel gears, an oscillatiiig bar at the side of such numberwheel g'ear, swinging arms on which said bar is pifvotally hung to provide endwise oscillation otsaidbar, a projection on said carrying gear to actuate said oscillating bar, and a pawl actuated by said oscillating bar adapted tocarry a number-wheel of different order.

(i, In combination with the number-wheel gears ot a computing machine, a carrying evice comprising a tripping gear in mesh with one of said endwise oscillating number-wheel number\vheel gears, an bar at the side'ofsuch gear, a projection on said caractuate said oscillating bar, a pawl actuated by said oscillating bar. adapted to carry a number-wheel of different or er, and a lock normally holding the last named number-wheel gear against rotation anddisengaged therefrom by said bar dur ingsaiid carrying operation.

7: Iri combinatioii with the nu mberwheel gears of. a computing machine having locks normally holding said gears against rota-' tion, a carrying device comprising a carry 'iiig'igcar in mesh with one of said numberwheel-gears, and mechanism actuated by mid carrying gear adapt-ed at a predetermined; pointin its rotation to actuate a number wheel gear of different order, and to unlock the lock engaging such number-wheel gear during said carrying operation, said mechanism being so timed as to withdraw said loclt before the number-wheel gear engaged thereby is rotated.

8,, In combination with the number-wheel gears of a computing machine, a-carrying device comprising a tripping gear in mesh with one of said number-wheel gears, an endwise oscillating bar at the side of such number-wheel gear, a projection on said car rvm ear to actuate said oscillati bar, a a

pawl actuated by said oscillating baradapted to earryanumbenwheel gear of different order, and a lock normally holding the last named, number-wheel gear against rotation and disengaged therefrom by said bar during saidcarrying'operation, the. action of said lock and said pawl being relatively so rotating in one direction,

timed that the withdrawal of the lock will begin before the pawl rotates said number wheel gear. 9, In combination with the main numberwheel gears offa computing machine, said gears adapted always to rotate in the same direction, a set of number-wheels actuated respectively by said main gears, each numberwheel bearing on its periphery a series of numerals, means to reverse the direction of rotation of said number-wheels without re versing the direction of rotation of the main gearsfsaid number-Wheels adapted to perform addition when rotated in one direction and subtraction when rotated in the opposite direction, and carrying devices adapted respectively to different order when their corresponding number-wheels, rotating in adding direction, pass from the-endto the beginning of said series of numerals, and rotating in subtracting direction, pass from the beginning to the end of: said series of numerah i j 10. In combination with the mairrnumher-wheel gears of a computing machine, a series of number-wheels actuated respectively by said main the direction of rotation of said numberwheels without reversing the direction of.

rotation-of said main gears, said numberwheels adapted to perform addition when rotated in one direction and subtraction when rotated in the opposite direction, andtwo sets or carrying main gears one set at gears engaging said a time, each gear of one set adapted to carry a main gear of different order when the number-wheels are l and each gear of the other set adapted to carry a main gear of different order when the number-wheels are rotating in the opposite direction.

11. In combination with the main number-wheel gears of a computing machine, a series of number-wheelsactuated respectively by said main gears, means to reverse the direction of rotation of said numberwheels without reversing the direction of rotation of said main gears, said numberwheels adapted to perform addition when rota ted ;in one direction and subtraction when rotated in the opposite direction, and two sets of carrying gears engaging said main gears one set at a time, each gear of one set adapted to carry a main gear of different order when the number-wheels are rotating in one direction, and each gear of the other set adapted to carry a main gear of different order when the number-wheels are rotating in the opposite direction, and connection between said carrying gears and said number-wheels, adapted automatically to shift the carrying gears to positions appropriate to the direction of rotation of the numberwheels.

'12. 'In combination with the main mum carry number-wheel gears 01 gears, means to reverse her-wheel gears and number-wheels of a computing machine, a series of pairs of gears adapted to engage their respective main gears one at a time to rotate the number-wheels, the gears of each pair being in mesh with each other and shiftable into and out of mesh with their corresponding main gears, whereby said number'wheels may, by shifting said pairs of gears, be rotated in either direction, to perform addition or subtraction, without reversing the direction of rotation of the main gears.

13. In combination with the main number-wheel gears and number-wheels of a computing machine, a series of pairs of gears adapted to engage their respective main gears one at a time to rotate the number-wheels, the gears of each pair being in mesh with each other and shiftable into and out of mesh with their corresponding main gears, whereby said number wheels may, by shifting said pairs of gears, be rotated in either direction, to perform addition or subtraction, without reversing the direction of rotation'of'the main gears, and carrying devices adapted respectively to carry number-wheels gears of different order when their corresponding number-wheels, rotating in adding direction, pass from the end of the beginning of the series of numerals on the number-wheels, and rotating in subtracting direct-ion; pass'from the beginning to the end of said'series of nuinerals.

14.- In combination with the main numher-wheel gears of a computing machine, a set of number-wheels, two sets of gears in mesh with each other adapted to engage said main gears one 'set ata time, to rotate the number wheels in either direction, and two sets of carrying gearsengaging said main gears one set at a time, each carrying gear of one set ada )ted to carry a main gear of different order when the numberwheels are rotating in one direction, and each carrying gear of the other set adapted to carry a main gear of different order when the number-wheels are rotating in the opposite direction.

15. In combination with the main number-wheel gears of a computing machine, a set of number-wheels, two sets of gears in mesh with each other adapted to engage said main gears one set at a time, to rotate the number-wheels in either direction, and two sets of carrying gears engaging said main gears one set at a time, each carrying gear of one set adapted to carry a main gear of different order when the number-wheels are rotating in one direction, and each carrying gear of the other set adapted to carry a main gear of different order when the num her-wheels are rotating in the opposite direction, and connection between the sets of gears which rotate the number-wheels and the sets of carrying gears, adapted to shift said sets of gears in unison, thereby bring ing the appropriate sets of gears into mesh with said main gears at the same time.

16. In combination with the main numberwheel gears of a computing machine, a series of number-wheels having gears fast thereto, shiftable into and out of mesh with said main gears and adapted to rotate the number-wheels in one direction when in mesh with said main gears, intermediate gears in mesh with said gears on the number-wheels and also shiftable into and out of mesh with said main gears and adapted when in mesh with said main gears to rotate said numberwheels in reverse direction, two sets of can rying gears in mesh with each other and adapted to engage said main gears one set at a time, the gears of one set adapted respectively to carry main gears of different order when the number-wheels are rotating in one direction, and the gears of the other set adapted respectively to carry main gears of different order when the number-wheels are rotating in the opposite direction.

17. In combination with the main number-wheel gears of a. computing machine, a rocker comprising two shafts extending across said main gears, a set of numberwheels having gears fast thereto, assembled on one of said shafts, and a set of intermediate gears meshing with the gears fast on the number-wheels, assembled on the other shaft, said sets of gears adapted to engage the main gears one set at a time by swing ing said rocker, thereby reversing the direction of rotation of the number-wheels, a second rocker comprising two shafts extending across the said main gears, each carrying a set of carrying gears, the gears of one set meshing respectively with the gears of the other set and adapted to engage the main gears one set at a time. by swinging the lastnamed rocker, one set of said carrying gears adapted to carry the main gears when the number-wheels are rotating in one direction, and the other set of carrying gears adapted to carry the main gears when the numberwheels are rotating in the opposite direction.

18. In combination with the main number-wheel gears of a con'ipnting machine, a rocker comprising two shafts extending across said main gears, a set of numberwheels having gears fast thereto, assembled on one of said shafts, and a set of intermediate gears meshing with the gears fast on the number-wheels, assembled on the other shaft, said sets adapted to engage the main gears one set. at a time by swinging said rocker, thereby reversing the (lil'OCtlOll of rotation of the nnn'iber-n-heels, a second rocker comprising two shafts extending across the said main gears, each carrying a set of carrying gears, the gears of one set meshing respectively with the gears of the other set and adapted to engage the main gears'one set at a time by swinging the last named rocker, one set of said carrying gears adapted to carry the main gears when the number wheels are rotating in one direction, and the other set of carr ing gears adapted to carry the main gears when the numberwheels are rotating in the opposite direction, said rockers being connected to swing in unison, thereby bringing the appropriate sets of gears carried by the two rockers into mesh with said main gears at the same time.

19. In combination with the main numher-wheel gears of a computing machine, a set 'of number-wheels actuated respectively by said;,main gears, each number-wheel bea r ing on its periphery a series of numerals, means to reverse the direction of rotation of said number-wheels, said number-wheels adapted to perform addition when rotated in one'direction and subtraction when rotated in tlie opposite direction, and carrying devices adapted respectively to trip number-wheelfgears of different order when their corresponding number-wheels, rotating in adding direction, pass from the end to the beginning of said series of numerals, and ro tating in subtracting direction, pass from theJbgirining to the end of said series of numerals, and a single shipper for reversing the number-wheels and the carrying devices.

20. In combination with the main number-wheel gears of a computing machine, a series of numbervheels actuated respectively by said main gears, means to reverse the direction of rotation of said numberwheels without reversing the direct-ion oi rotation of said main gears, said numberwheels adapted to perform addition when rotated in one direction and subtraction when rotated in the opposite direction, and two sets of carrying gears engaging said main gears one set at a time, each gear of one set adapted to carry a main gear of a different order when the number-wheels are rotating in' one direction, and each gear of the other set adapted .to carry a main gear of diflerent order when the number-wheels are rotating in the opposite direction, and a single shipper for reversing the number wheels and the carrying gears.

21. In combination with the main numher-wheel gears of a computing machine, a rocker comprising two shafts extending across said main gears, a set of numberwheels having gears fast thereto, assembled on one of said shafts, and a set of intermediate gears in mesh with said gears fastto the number-wheels, assembled on the other shaft, said sets adapted to engage the main gears one set at a time by swinging said rocker, thereby reversincr the direction of rotation of the number-w eels, a second rocker comprising two shafts extending messes across the said main gears, each carrying a set of tripping gears, the gears of one set meshing respectively with the gears of theother set and adapted to engage the main gears one set at a time by swinging the'last named rocker, one set of said carrying gears adapted to carry the main gears when" the number-wheels are rotating in one direction, and the other set of carrying gears adapted to carry the main gears when the numberwheels are rotating in the opposite direction, and a single shipper adapted to shift said rockers in unison, to bring the appropriate sets of gears carried by the two rockers into mesh with said main gears at the same time.

22. In combination with the main number-wheel gears of a computing machine,- a rocker comprising two shafts extending across said main gears, a set of'numberwheels having gears 'fast thereto, assembled on one ofsaid shafts, and a set of intermediate gears in mesh with said gears fast to the number-wheels, assembled onthe other shaft, said sets adapted to engage the main gears one set at a time by swingin said rocker, thereby reversing the direction of rotation of the number wheels, a second rocker comprising two shafts extending across the said main gears,each carrying a set of carrying gears, the gears of oneset meshing respectively with the gears of the other set and adapted to engage the main gears one set at a time by swinging the last named rocker, one set of said carrying gears adapted to carry the main gears whenthe number-wheels are rotating in one direction, and the other set of carrying gears adapted to carry the main gears when the number- 7 wheels are rotating in the opposite direction,

and printing-hammer actuating mechanism adapted when operated, automatically to swing said number-wheels to their position away from the main gear wheels.

23. In combination with the main number-wheel gears of a computing machine, carrying devices suitable for'both adding and subtracting operations, comprising two carrying gears meshing with each other and adapted to engage one of said'main gears one at a time, an oscillating bar actuating a pawl adapted to carry a. main numberwheel gear of different order, and projections carried by said carrying gears each adapted at a predetermined point in the rotation of its gear to actuate said bar to cause the pawl to carry the main gear of different order when its own carrying gear is in mesh with the main ear.

24. In combination with the main number-wheel gears of a computing machine, carrying devices suitable for'both adding and subtracting operations, comprising two carrying gears meshing with each other and adapted to engage one of said main gears one at a time, an oscillating bar actuating a pawl adapted to carry a main numberwheel gear of different order, two projections on said bar, and projections carried by said carrying gears, each adapted at a predetermined point in the rotation of its own gear to engage one of said projections on said bar and thereby actuate said bar and pawl when its own carrying gear is in mesh with the main gear, and to clear such projection on the bar when its own gear is out of mesh with the main gear.

25. In combination with the main number-Wheel gears of a computing machine, locks normally holding said main gears immovable, and carrying devices suitable for both adding and subtracting operations, comprising two carrying gears meshing with each other and adapted to engage one of said main gears one at a time, an oscillating bar actuated by either of said carrying gears when in mesh with its main gear, a pawl actuated by said bar adapted when operated to carry a main number-Wheel gear of different order and positively to arrest the same at the end of its predetermined carrying movement, and means operated by said bar to unlock the lock of the main gear being carried during said carrying operation, and means to restore said bar, pawl and lock to their initial positions at the end of each carrying operation.

Signed by me at Boston, Massachusetts, this seventeenth day of July, 1912.

GEORGE WALKER. Witnesses:

ROBERT CUSHMAN, CHARLES D. \VooDBEnRY.

Copies 01' this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G." 

